In the related art, there is known a bearing roller chain in which a plurality of anti-friction rollers is arranged between an outer circumferential surface of a cylindrical bush, which interconnects inner plates facing each other, and an inner circumferential surface of a cylindrical roller, into which the bush is inserted. In this bearing roller chain, flanges are integrally formed with the opposite end portions of the inner circumferential surface of the roller, thereby forming a recess that holds the anti-friction rollers. The roller is filled with a lubricant that lubricates the rotation of the anti-friction rollers.
In the bearing roller chain mentioned above, the roller, the flanges and the anti-friction rollers are usually made of metals. For that reason, during the use of the bearing roller chain, high frictional heat is generated due to the rotation of the anti-friction rollers, particularly due to the friction of the anti-friction rollers and the flanges, i.e., the friction of metals. In this case, however, when the temperature of the lubricant is increased by the frictional heat, the viscosity of the lubricant decreases and the lubricant within the roller tends to leak to the outside of the roller. As a result, there is posed a problem in that due to the leak, the lubricant for rotating the anti-friction rollers may become insufficient and the wear resistance decreases.